We are given the following point: (3,15)
A vertical line is a line of the form:
[tex]x=k[/tex]The value of "k" is the x-coordinate of the given point, that is:
[tex]x=3[/tex]A horizontal line is a line of the form:
[tex]y=k[/tex]Where "k" is the y-coordinate of the given point, that is:
[tex]y=15[/tex]